Physics of Chromospheric Evaporation in Solar Flares K. Shibata ２００３. Apr ２８ Solar Seminar

Best 10 of Most cited papers based on Hida-DST observations 6 th -10 th (ADS ： 2003 Apr 27) 6. Brueckner, G. E., et al. (1988) ApJ, 335, 回 7. Kurokawa, H., Hanaoka, H., et al. (1987) Solar Phys., 108, Tsubaki, T., et al. (1988) PASJ, 40, Culhane, J. L. et al. (1994) Solar Phys., 153, Kitai, R. (1986) Solar Phys., 104,

Best 10 of Most cited papers based on Hida-DST observations 1 st – 5 th 1. ２. Ichimoto, K. (1987) Solar Phys. 39, ３． Kurokawa, H., (1987) Solar Phys., 113, ４. Kurokawa, H. (1989) Space Sci. Rev. 51, Kurokawa, H., Takakura, T., et al. (1988) PASJ, 40, Ichimoto, K. and Kurokawa, H. (1984) Solar Phys. 93, 回

Introduction: what is flare ? Preflare energy buid-up Trigger Energy release --- magnetic reconnection –Heating –Particle acceleration –Mass ejection –Shock wave Energy transport –Nonthermal electron beam –Heat conduction –Chromospheric evaporation –Radiation

Energy buidup

Energy release – magnetic reconnection Unified model (Shibata 1997)

Energy transport Bright soft X-ray Flare loop Is a Consequence of chromospheric evaporation !

Neupert (1968) ApJ 153, 59 obs. soft X-ray line + microwave in flares => “additional material, not originally at coronal temperature, is rapidly heated and elevated to high stages of ionization during the event”

Neupert effect Time derivative of soft X-ray intensity ~ hard X-ray intensity Hard X-ray microwave Soft X-ray Dennis and Zarro (1993) OK(80%) Lee et al. (1995) no Tomczak (1999) spatial info OK

Theory and numerical simulations of chromospheric evaporation

Hirayama (1974) “Particles observed in the corona and the solar wind are evaporated from the chromosphere during the flare”

t － 2/7 ∝ T = const. Evaporation cooling (Antiochos and Sturrock 1978)

Nagai (1980) Solar Phys. 1D-Hydro-sim. F ~ 3x10^{9} erg/cm^2/s

Nagai (1980) F ~ 3x10^{9} erg/cm^2/s

Nagai (1980) F ~ 3x10^{9} erg/cm^2/s

Nagai (1980) F ~ 3x10^{9} erg/cm^2/s

Nagai (1980) F ~ 3x10^{10} erg/cm^2/s Strong downflow ~ 40km/s

Fisher et al. (1985) ApJ thick target heating by nonthermal electrons

Scaling law (Fisher 1985) Flare maximum temperature Maximum velocity of evaporation upward flow

MHD Simulation of Reconnection with Heat Conduction and Chromospheric Evaporation (Yokoyama and Shibata 1998, 2001)

Reconnection heating = conduction cooling Flare temperature scaling law （ Yokoyama and Shibata 1998 ）

Simulation of soft X-ray and radio observations

Prediction of Yokoyama-Shibata 1998

Observational evidence of chromospheric evaporation

Antonucci et al. (1982) SP 78, 107 detected blue shift of evaporation upward flow

Antonucci et al. (1982)

Ichimoto and Kurokawa (1984) SP 93, 105 solved red asymmetry problem “The spectroscopy of Ichimoto and Kurokawa (1984) represents the zenith of what has been achieved up to now by conventional photographic spectroscopy” (Canfield et al. 1990)

Can red asymmetry be explained by absorbing material ?

Redshift cannot be explained by absorbtion

Temporal variation of downward velocity in the flare emitting region (Ichimoto and Kurokawa 1984) ● wing shift x peak shift ○ Halpha intensity

Ichimoto and Kurokawa (1984) H alpha red asymmetry ( km/s) is is due to downward motion of the compressed chromospheric flare region produced by the impulsive heating by energetic electrons or thermal conduction

Canfield et al. (1990) H alpha + Hard X-ray confirm Ichimoto-Kurokawa, but show also blue shifted H alpha emssion

Wuelser et al. (1992) ApJ 384, 341 SMM X-ray + Sacpeak H alpha line upflowing coronal material (as seen in Ca XIX soft X-rays) and downflowing chromospheric material (as seen in redshifted H alpha) appear simultaneously at the beginning of impuslive hard X-ray emission, with the total momenta of oppositely directed plasmas being equal to the observational uncertainties

Wuelser et al. (1992)

Nogami, Brooks, Isobe, Shibata,,, ( ) We want to observe stellar flares with the scientific purpose similar to that of Wuelser et al. (1992)’s solar flare observations by using both Subaru and XMM-Newton

Further developments Wuelser et al. (1994) –Yohkoh-Mees –Upflowing coronal plasma and downflowing chromospheric plasma at the same locations, at footpoints of a soft X-ray loop –Footpoints are not heated by nonthermal electrons but by heat conduction Shoji and Kurokawa (1995) –Hida DST –Impulsive phase spectra of flares for Halpha, CaIIK, HeID3, NaID1,2, other metalic lines –Emitting region of chromospheric flare consists of two regions; –Thin fast downward moving layer, and stationary optically thick layter (for metalic lines)

Latest paper Teriaca et al. (2003) ApJ 588, 596 –SOHO/CDS, SacPeak, GOES first quasi-simultaneous and spatially resolved observations of velocity fields during the impulsive phase of a flare, in both the chromosphere and upper atmospehre

Shimojo et al. (2001) evaporation occurs also in X-ray jets (see also Miyagoshi and Yokoyama 2003)

Shimojo-Shibata (2000) ApJ

X-ray jets are evaporation flows (Shimojo and Shibata 2000)

Future Subjects Spectroscopic observatsions of flares should be done at Hida with DST as the most important priority projects in 2003 H alpha red asymmetry of surges would be observed (at the footpoint of surges/X-ray jets) stellar flares observations will be interesting to detect evaporation flows Remaining puzzles: –blue shifts ? –Nonthermal electrons or thermal conduction ? Develop further MHD simulations with evaporation in 2D and 3D, incorporating effects of nonequilibrium ionization, nonthermal electrons, and radiative transfer

飛騨天文台観測論文引用ベスト１ ０ ADS 調べ： 2003 年 4 月２７日 1. Ichimoto, K. and Kurokawa, H. (1984) Solar Phys. 93, 回 2. Ichimoto, K., Kubota, J., et al. (1985) Nature, 316, Oda, N. (1984) Solar Phys. 93, Hanaoka, Y., Kurokawa, H., et al. (1994) PASJ, 46, Ichimoto, K. (1987) Solar Phys. 39,

6. Kurokawa, H., (1987) Solar Phys., 113, 回 7. Kurokawa, H. (1989) Space Sci. Rev. 51, Kawaguchi, I. (1980) Solar Phys. 65, Kitai, R. and Muller, R. (1984) Solar Phys. 77, Kurokawa, H., Takakura, T., et al. (1988) PASJ, 40,

11. Brueckner, G. E., et al. (1988) ApJ, 335, 回 12. Kurokawa, H., Hanaoka, H., et al. (1987) Solar Phys., 108, Tsubaki, T., et al. (1988) PASJ, 40,

Al.1 Al Mg 実際のデータで 見てみましょう

温度は・・・

cooling mechanism conductive cooling ２．２．２ 理論から予測される cooling

evaporation の 効果無し （密度一 定） evaporation の 効果有り （密度変 化） t － 2/5 ∝ T (Antiochos and Sturrock, 1978) 詳細 t － 2/7 ∝ T conduction & evaporation

コロナ（密度 小） 彩層（密度 大） evaporation により、ループ内 の密度が上昇する。 彩層蒸発 熱伝導が彩層へ evaporation （彩層蒸発）

２．２．３． 理論と観測値の 比較 フレア全体 Local －０．２８１ －０．１８７ t － 2/7 ) ∝ ( T ‐ 2/7 = ‐０．２８６ 比較 その１（９７ / １１ / ０６）

比較 その２（９４ / １１ / １３） Local フレア全体 －０．２４１－０．１７７

Local フレア全 体 97/11/06 －０．２８１ －０．１８７ 94/11/13 －０．２４１ －０．１７７ t － 2/7 ∝ T (evaporation 効果有り ) とよく一致 cooling が 緩やか 観測値まとめ

２．４ 結 論 Yohkoh の温度域（ ）で、 （１） cooling mechanism ⇒ conduction cooling （２） フレア全体解析 → （１）より 緩やか Local な解析 → （１）とほ ぼ同じ

・戻る t － 2/5 ∝ T evaporation 無し

t － 2/7 ∝ T = 一定 ・戻る evaporation 有り